ladies t-shirts

I am currently setting up a website selling t-shirts.I don’t know much about
women’s tee’s. I would appreciate any help that I can get in relation to
screenprinting companies with good quality work at good prices. There seems to
be so many companies out there. I have a good design idea but no experience in
this field. Is it better (or cheaper!) to buy blanks and then find a
screenprinter or no?. Can anyone tell me if printing on spandex causes any
problems? I would like to perhaps sell scoop-neck, v-neck, tank-tops, regular
tee’s and halternecks. What sizes and colors sell best? Any particular brand (
or style within a brand) sells best/lasts longer/holds color? Any information
you can give me on any of these subjects or any you think are related I would be
glad to hear about.Any advice is warmly welcomed! Thank you!